Power supply systems are known that include a storage cell (battery) in addition to a power generator. These can store a difference between power generated by the power generator (generated power) and power consumed by a load (consumed power) as excess power in the storage cell. See, for example, Japanese Patent Application Publication No. 2011-103740 the entire contents of which, and particularly disclosure in and related to Paragraph [0047] are incorporated specifically by reference.
Such systems concern power shortage differences between power that needs to be supplied to the load (demand power) and power generated by the power generator such as a solar cell (generated power). The system covers the power shortage by discharging the storage cell (battery). In short, the storage cell in this patent literature charges excess power expressed by “generated power−consumed power” and discharges to cover the power shortage expressed by “demand power−generated power.”